i'm putting in a new clutch assembly in my car. so while i have my M6 & clutch assembly out of the car, should i look at upgrading other things? isn't there a better tranny mount? what else?

 

You can substitute a polyurethane mount for the stock rubber mount, but if you haven't had a problem with the stocker, and it appears to be in good condition, probably be best to just leave it alone. Some people find there is too much vibration transmitted to the shifter with the Energy Suspension poly mount. I've had one for 12 years though, first under the stock T56 and now under a TH400 and I didn't have any vibration problems.

You also need to check the bushing in the torque arm mount, that bolts to the tailshaft of the tranny. You can get a poly bushing for that as well, and when I still had the stock torque arm, mounted in the stock location, I thought it helped increase the front end lift on launch.... but if you do the poly TA bushing, I would definitely do the poly tranny mount to deal with the harsher forces transmitted to the tailshaft of the tranny.